1. Field of the Invention
The present invention generally relates to computer software. More specifically, the present invention relates to a computer software application that facilitates the interactive design of three dimensional (3-D) structures based on cross-section frameworks.
2. Description of the Related Art
Currently, computer aided design (CAD) applications are available that allow a designer or engineer to build a computer model of a real-world 3-D object. Such models are generally based on the real-world geometry of the object being modeled.
Many real-world structures may be modeled as a longitudinal structure, composed from a series of repeating cross-sectional elements. For example, a CAD model of road may be modeled as a series of individual cross-sections, and each cross-section may be specified by a collection of parameters that specify the geometry and characteristics of the cross-section. In addition to roadway lanes, other examples of structures that may be modeled as a series of repeating cross-sections include, sidewalks, tunnels, dams, bridges, runways, pipelines, individual pipes, and the like.
Accordingly, some current CAD applications allow users to generate a 3-D model using a series of cross-section elements integrated into a single a longitudinal structure. In most cases, however, the cross-section elements that may be placed into the CAD model are limited to those provided by the particular CAD application. Given the virtually infinite variety of real world variation that occurs in the actual cross-sections of these structures, however, the unavailability of an adequate number of cross-sections has, historically, been a severe limitation on the usefulness of current CAD applications.
At the same time, simply providing additional cross-section elements for a CAD application has proven to be both cost prohibitive and time consuming. Further, efforts to provide users with a CAD application that allows a designer to specify each cross-section with the required real-word variation has led to overly complex CAD applications that have been difficult and cumbersome for designers to use. Hence, these CAD applications have failed to gain widespread acceptance.
Accordingly, there remains a need for an improved CAD application that allows a designer to generate a model of a 3-D longitudinal structure as a series of repeating cross-sectional elements. Preferably, such a CAD application would allow users to create cross-sectional elements with enough variety so as to be useful in modeling real-world structures, without requiring a system that defines all of the different possible cross-section elements in advance, and without exhibiting the complexity present in current systems.